/Engine/Source/Runtime/MeshDescription/Public/MeshDescriptionBase.h
Returns reference to an array of VertexInstance IDs instanced from this vertex
void GetVertexVertexInstances ( [FVertexID](API\Runtime\MeshDescription\FVertexID) VertexID, [TArray](API\Runtime\Core\Containers\TArray)< [FVertexInstanceID](API\Runtime\MeshDescription\FVertexInstanceID) > & OutVertexInstanceIDs ) const